To better manage and optimize storage, a conventional computer system usually pools several disk partitions as a storage pool, then builds a Redundant Array of Independent Disks (RAID) on the storage pool, and performs linear logical block address (LBA) mapping between RAID extents and logical units (LUN) through a RAID mapping table (RMT), thereby implementing mapping the user's I/O data to the disk.
The above linear mapping manner has advantages such as simple algorithm. However, since the user's I/O after the linear mapping usually only concentrates in partial RAID extents and cannot be evenly distributed on the whole disk space, the heat generation of the storage device is uneven, and the I/O performance of the whole storage device is substantially reduced, and particularly the I/P per second (IOPS) performance is remarkably reduced.